document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=184157>Question 184157</A>: <I><SPAN STYLE=\"word-break: break-all;\"> (a) Plot the data on U.S. general aviation shipments. (b) Describe the pattern and discuss possible causes. (c) Would a fitted trend be helpful? Explain. (d) Make a similar graph for 1992–2003 only. Would a fitted trend be helpful in making a prediction for 2004? (e) Fit a trend model of your choice to the 1992–2003 data. (f) Make a forecast for 2004, using either the fitted trend model or a judgment forecast. Why is it best to ignore earlier years in this data set? Airplanes<BR>\n" );
document.write( "U.S. Manufactured General Aviation Shipments, 1966–2003<BR>\n" );
document.write( "Year Planes    Year Planes      Year Planes       Year Planes<BR>\n" );
document.write( "1966 15,587   1976 15,451     1986 1,495          1996 1,053<BR>\n" );
document.write( "1967 13,484    1977 16,904    1987 1,085          1997 1,482<BR>\n" );
document.write( "1968 13,556    1978 17,811    1988 1,143          1998 2,115<BR>\n" );
document.write( "1969 12,407    1979 17,048    1989 1,535          1999 2,421<BR>\n" );
document.write( "1970 7,277      1980 11,877    1990 1,134           2000 2,714<BR>\n" );
document.write( "1971 7,346      1981 9,457      1991 1,021           2001 2,538<BR>\n" );
document.write( "1972 9,774      1982 4,266      1992 856              2002 2,169<BR>\n" );
document.write( "1973 13,646    1983 2,691      1993 870               2003 2,090<BR>\n" );
document.write( "1974 14,166    1984 2,431      1994 881<BR>\n" );
document.write( "1975 14,056    1985 2,029       1995 1,028<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #138184 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=138184\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> These are all judgement questions.<BR>\n" );
document.write( "You should be able to sketch a dot-plot<BR>\n" );
document.write( "of the numbers against the years and<BR>\n" );
document.write( "describe increase intervals and decrease<BR>\n" );
document.write( "intervals. \"Fitted trend\" is a descriptive<BR>\n" );
document.write( "term for \"do you see a pattern?\".<BR>\n" );
document.write( "--------<BR>\n" );
document.write( "The rest of the problem is similarly <BR>\n" );
document.write( "descriptive.<BR>\n" );
document.write( "------------<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );